In other words, his last week on the job was like many others in his 405-day tenure as the nation's top diplomat — the shortest of any secretary of State to begin an administration since Elihu B. Washburne's 11-day service in 1869.

Tillerson often found himself on the outer ring of President Trump's inner circle, trying to interpret the president's mercurial and contradictory foreign policy to the rest of the world.

He reassured NATO allies that the United States remained committed to the alliance after the president threatened to pull out over "dues" that Trump said were owed directly to the United States. (They weren't.)

He engaged with North Korea despite the president's protests — again via Twitter — that he was "wasting his time trying to negotiate with Little Rocket Man.”

And he tried to salvage the Iran nuclear deal through a European-brokered fix to the Obama-era agreement rather than having Trump scuttle the deal completely.

In explaining his break with Tillerson on Tuesday, Trump specifically cited those differences over the Iran deal: "I think it's terrible. I guess he feels it was OK."

But Trump's comments give a glimpse into why he's making this move now.

Trump is heading into an unprecedented face-to-face meeting with North Korea's Kim Jong Un over that country's nuclear program. The timing of Tillerson's dismissal was designed to allow Trump to put a new team in place before those talks, a White House official said on condition of anonymity to discuss a personnel decision.

Trump's nominee to replace Tillerson is CIA Director Mike Pompeo, whose hard-line stances on Iran and North Korea are closer to Trump's.

Trump conceded Tuesday that he and Tillerson often were not on the same page. "I actually got along well with Rex, but really, it was a different mind-set. It was a different thinking.

"With Mike Pompeo," he said, "we have a similar thought process."

North Korea hawks applauded Pompeo's nomination. "No one understands the threat posed by North Korea and Iran better than he does," said Sen. Lindsay Graham, R-S.C.

But Sen. Ben Cardin, D-Md., said he feared Trump was stocking his Cabinet with yes men. "It is disturbing to see such a high-level change in our diplomatic team as negotiations with North Korea move into a new and delicate stage," he said.

While Tillerson was in Africa last week, it was Pompeo who explained Trump's unexpected rapprochement with North Korea on CBS' Face the Nation Sunday.

Pompeo would not be pinned down on whether he or the secretary of State would lead the preliminary talks before the Trump-Kim summit. His appointment to Tillerson's post would resolve that conflict and put him unambiguously in charge of getting Trump and Kim to the table.

The White House announced the personnel moves through an increasingly common playbook: a leak, a tweet and written statements from those involved. In this case: Trump, Pompeo and CIA nominee Gina Haspel.

Conspicuously missing: a statement from Tillerson himself.

Tillerson's side of the story came from Steve Goldstein, undersecretary of State for public diplomacy.

"The secretary had every intention of staying because of critical progress made in national security," he said. "The secretary did not speak to the president and is unaware of the reason."

Goldstein was then fired for contradicting the White House's account of Tillerson's dismissal.

Later, Tillerson appeared in a State Department auditorium to give a statement to reporters. He talked about the hard work it took to get North Korea to the table: ending President Obama's policy of "strategic patience" and replacing it with a maximum-pressure campaign to rally the world to impose punishing sanctions on the North Korean regime.

He thanked his diplomats, the military and the American people — but not Trump.

A look at Secretary of State Rex Tillerson

Secretary of State Rex Tillerson holds up a Boy Scout scarf that his wife Brenda placed on him at the end of his talk at the Summit Bechtel Family National Scout Reserve in Glen Jean, W.Va. on July 21, 2017. The Boy Scouts unveiled a bronze statue of Tillerson and presented him with a flag and smaller replica statue.

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Secretary of State Rex Tillerson holds up a Boy Scout scarf that his wife Brenda placed on him at the end of his talk at the Summit Bechtel Family National Scout Reserve in Glen Jean, W.Va. on July 21, 2017. The Boy Scouts unveiled a bronze statue of Tillerson and presented him with a flag and smaller replica statue.